Fossils show big bug ruled the seas 460 million years ago

New York: Earth’s first big predatory monster was a weird water bug, newly found fossils show.

Almost half a billion years ago, Earth’s dominant large predator was a sea scorpion that grew to 5 feet 7 inches, or 170 centimetres, with a dozen claw arms sprouting from its head, according to a new study.

Scientists found signs of these new monsters deep in Iowa.

Geologists at the Iowa Geological Survey found 150 pieces of fossils about 60 feet, or 18 meters, under the Upper Iowa River. Scientists at Yale University determined they were a new species from about 460 million years ago, when Iowa was under an ocean.

“This is the first real big predator,” lead author of the study, James Lamsdell said. “I wouldn’t have wanted to be swimming with it. There’s something about bugs. When they’re a certain size, they shouldn’t be allowed to get bigger.”

This creature is named Pentecopterus decorahensis after an ancient Greek warship and is not a bug by science definitions, Dr. Lamsdell said. It’s part of the eurypterid family.

Those type of creatures “are really cool,” said Joe Hannibal, curator of invertebrate paleontology at the Cleveland Museum of Natural History. Hannibal wasn’t part of the study, but praised it for being well done, adding “this species is not particularly bizarre for a eurypterid.”

Unlike modern land scorpions, this creature’s tail didn’t sting. It was used more for balance and in swimming, but half this creature’s length was tail, Dr. Lamsdell said.

There were larger sea scorpions halfway around the world at the same time but those were more bottom feeders instead of dominant predators, he said.

“It was obviously a very aggressive animal,” he said. “It was a big angry bug.”

Keywords: Iowa Geological Survey, Iowa, Pentecopterus decorahensis